Invasive Species Management

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Help Jeffco ISM provide residents with the information they need to manage noxious weeds and to gauge how our efforts are doing.

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Need Noxious Weed Advice?

We are not able to provide site visits in 2020 but are monitoring calls and questions. See our contact information on the right-hand side of this page.

What We Do

The Jefferson County Invasive Species Management program provides education and outreach to help Jeffco residents learn to identify and manage noxious weeds, forest insect pests and agricultural vertebrate pests.  Our goal is to provide the public with information and offer solutions that they can use to manage their weed and pest problems.

We ensure the compliance with Colorado’s noxious weed, forest pest, and agricultural vertebrate pest regulations on private, county, and state lands.  We also provide technical assistance and support to county departments who are responsible for managing county owned lands.

The program coordinates with private, local, state, and federal agencies to achieve regional pest control.

Who We Are

Our staff includes the Invasive Species Management Coordinator and limited summer help.

cellophane bee image source: bugguide

Bee of the Month - January 2021

Each month we will feature a bee profile.  There are 100’s of species of native bees in Jeffco.  Bees support many ecological processes but often go unnoticed.  

Compact Cellophane Bee

Colletes compactus 

Photo credit: bugguide

The compact cellophane bee is a late summer emerging ground nesting bee species. These bees dig long narrow nest tunnels deep into bare soil and then create horizontal off shoots from the main tunnel in which they lay their eggs. This species is a solitary bee, meaning there is only one female bee in each nest. The “queen” gathers pollen and nectar from nearby flowers and creates pollen balls (a combination of pollen and nectar molded into a small ball like structure) on top of which they lay one single egg. Once an egg and pollen ball are placed into the horizontal tunnel, it is closed and sealed off.

Cellophane bees line their nest cells with a material that is waterproof and looks like plastic when it is dry, hence their name, cellophane or polyester bees. These bees have a forked tongue that allows them to create this unique material. In addition to the waterproofing, bees in this genus also line their nest cells with a natural bactericide and fungicide, linalool, for extra protection against diseases.

Although this species is solitary, females have been known to nest in aggregations, so there can be hundreds of bees in the same area. All bees in the genus Colletes are non-aggressive, so these aggregations are a great place to witness solitary ground nesting bees in action!

Dalmatian toadflax

Weed of the Month

Each month we will feature a noxious weed to help landowners identify weeds they may encounter on their property.

January 2021

Broad-leaved Dalmatian Toadflax Linaria dalmatica

Narrow-leaved Dalmatian Toadflax Linaria genistifolia

Dalmatian toadflax is an herbaceous perennial found in rangeland, pastures, rights-of-way, and disturbed areas.  An escaped ornamental, it was first brought to North America in the 18th century.  Records show that it has been in Colorado since 1905

Plants grow to about 3 feet tall.  Leaves grasp the stem and can be heart-shaped (Broad-leaved) or more narrow (narrow-leaved).  Leaves reduce in size as they near the tip of the stems.  Foliage and stems are grayish-green and have a waxy surface.

Plants flower between May-October.  Flowers are snapdragon-shaped, pale to bright yellow with a spur.  

Broad-leaved Dalmatian toadflax can produce up to 500,000 seeds per plant.  Seeds may remain dormant for up to 10 years in the soil. 

Broad-leaved Dalmatian toadflax has a deep taproot and lateral secondary roots that produce new plants from buds.  Narrow-leaved toadflax has rhizomes.  Both reproduce by seed and vegetatively.

Integrated management techniques include biological, chemical, and mechanical.

Dalmatian toadflax is known to hybridize with Yellow toadflax (Linaria vulgaris). The hybrid is fertile and shows varying characteristics of the parents.


Montana’s Noxious Weed Field Guide

CABI - Invasive Species Compendium

A Landowner's Guide

Developing a Noxious Weed Management Plan

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Download your copy

Weed Spotter

The Weed Spotter program is a citizen science based effort to detect 6 high priority species on Jeffco Open Space parks.  Learn more at our Citizen Science page.


Colorado’s Noxious Weed Awareness Campaign

2020 marked the 30th anniversary of the Noxious Weed Law. Jeffco Invasive Species Management is a partner in Colorado’s Noxious Weed Awareness Campaign.